What's the Welding Torch

We all familiar with the welding equipments like Plasma Welding Machine,welding Mask is also necessary too.So what about the Welding Torch.
Welding Torch that is used to control the gas mixture ratio, flow and flame when gas welding, and used for welding tools, known as the torch or gun. The role of the welding torch is to combustible gas and oxygen by a certain percentage of mixed and sprayed at a rate of combustion and generate a certain energy, composition and shape of a stable welding flame. Including suction and pressure type.